Kitaev Honeycomb — Majorana Flux Sectors

Exactly solvable spin liquid: Z₂ fluxes, Majorana fermions, non-Abelian anyons

A phase (gapped, Abelian)
B phase (gapless/gapped, non-Abelian)
Flux (vison) excitation
Kitaev honeycomb model: spins on a honeycomb lattice with bond-dependent interactions Jx, Jy, Jz. Exactly solvable via Majorana fermion representation. The phase diagram has three gapped A phases and one B phase.
H = −Jx Σx-bonds σˣσˣ − Jy Σy-bonds σʸσʸ − Jz Σz-bonds σᶻσᶻ
B phase (center): gapless Dirac fermions. Adding κ (time-reversal breaking) opens a gap and creates non-Abelian anyons (Ising anyons, related to Majorana zero modes). Z₂ fluxes (visons) are anyonic excitations living in plaquettes — green hexagons.